The process is too complicated to list here. Go to the link below and look up on-line owner's manual for detailed instructions.
The Desert Eagle was made in several calibers- one of which WAS the .44 magnum.
Machine Pistols -- PP2000 G18 M93 Raffica TMP Pistols -- USP.45 44.Magnum M9 Desert Eagle
No. While Dan Wesson DID make a .44 Magnum revolver, it was not known as a Desert Eagle. IMI made a .44 magnum Desert Eagle Auto pistol, but not a revolver.
.44 Mag is a cartridge and Desert Eagle is a pistol. Therefore they cannot be compared. The Desert Eagle comes in various calibers including .44 Magnum. The .50 AE is the bigger cartridge often used in the Desert Eagle, and almost always in movies. I will go out on a limb and assume that you mean this. The .50 AE is a bigger and more powerful cartridge than the .44 Magnum.
Yes
There's a .44 Magnum variant of the Desert Eagle.
In a .44 Magnum revolver, yes. In a semi-automatic .44 Magnum (such as the Desert Eagle), no.
100-400 USD
The Desert Eagle is capable of using either .44 or .50 caliber ammunition, although the .50 requires a barrel swap.
The Desert Eagle is available in .44 Magnum, among other calibres. So this would obviously be a moot point to compare. If you're referring to the .50 Action Express cartridge, which some Desert Eagle pistols are built for, then it would be the more powerful cartridge, over the .44.
The Desert Eagle comes in the following calibres: .50 Action Express .44 Magnum .357 Magnum .440 Cor-bon .41 Magnum .357/44 Bains and Davis (Israeli Prototype only)